1. Field of the Invention
The present invention relates to athletic shoe technology. More particularly, it relates to systems and methods for various forms of energy-translating soles, or platforms, or inserts, which are incorporated into footwear and are designed to more effectively transfer gravitational, inertial and ground reaction forces into linear momentum thereby promoting a more efficient running technique.
2. Description of the Related Art
Athletic shoe technology has undergone a revolution over the past thirty years, particularly in regards to improvements in running shoes, both for the professional and casual user. In general, the majority of advancements in running shoe technology have largely centered around support, shock absorption and energy efficiency. For example, U.S. Pat. No. 5,909,948 describes an athletic shoe sole having a lateral stability element to provide improved lateral support during heel-strike. U.S. Pat. Nos. 5,247,742 and 5,297,349 describe a cushioning sole for athletic shoes having a pronation control device incorporated into the midsole in order to increase the resistance to compression of the midsole from the lateral side to a maximum along the medial side, and U.S. Pat. No. 5,987,779 describes an athletic shoe having an inflatable tongue or bladder for a more secure fit.
A major focus in athletic shoe technology has centered on shock absorption. A number of patents describe various systems for shock absorption, such as air channels, miniature pumps, hydraulic systems, gas-filled bladders, elastomeric foam elements, pneumatic inflation devices and spring elements. The following are illustrative of such technologies: U.S. Pat. No. 5,598,645, U.S. Pat. No. 4,535,553, U.S. Pat. No. 5,325,964, U.S. Pat. No. 5,353,523, U.S. Pat. No. 5,839,209, U.S. Pat. No. 5,983,529 and U.S. Pat. No. 4,763,426.
Embodiments of the present invention are distinct from the athletic shoe technologies pertaining to additional support or shock absorption described above in that systems and methods of the present invention focus on locomotion efficiency.
There have been several shoe systems related to increasing energy efficiency during running, such as U.S. Pat. No. 4,358,902, which describes a thrust-producing shoe comprising a sole having fluid-filled cavities located in the heel and metatarsal portions with passageways interconnecting the fluid-filled cavities. As the heel cavity is compressed, fluid is forced through the passageways into the metatarsal cavities thereby providing shock absorption and forward thrust in the heel and metatarsal area.
U.S. Pat. No. 4,030,213 discloses a sporting shoe having an auxiliary sole member that is relatively thick under the toe portion and its outer surface is curved to form nearly a half circle at the forward extremity of the toe section and the rearward extremity at the ball of the foot is relatively flat. An additional embodiment describes a plurality of recesses within the sole of the shoe for housing a number of coil springs.
U.S. Pat. No. 4,506,460 describes a spring moderator for articles of footwear, wherein a high modulus moderator is positioned beneath the heel or forefoot with a cushioning medium beneath the moderator. The spring moderator operates to absorb, redistribute and store the energy of localized loads.
U.S. Pat. No. 4,936,030 provides an energy efficient running shoe having an energy-transmission mechanism in the heel portion of the sole to transmit the mechanical energy of heel impact to the storage/thrust mechanism in the front sloe portion, where it is stored and released during thrust. A number of embodiments are described having sophisticated systems employing lever arms, coils springs, hydraulic assemblies and the like for capturing and transferring mechanical energy.
U.S. Pat. No. 4,949,476 discloses a running shoe having a hard front sole for retaining gripping elements and, from the ball to the shank of the foot, an upwardly extending support cup on the outside of the shoe upper. The front sole extends into the shank portion of the shoe and covers a support wedge member. The wedge member extends from the ball of the foot to the shank and is progressively thicker towards the rear portion of the shoe. The wedge shaped member causes the foot to be brought into an extended position for emphasizing contact with the ground with the front outside ball region of the foot. This configuration serves to increase running efficiency by keeping the heel in an elevated position, which is the preferred attitude during sprinting.
U.S. Pat. No. 5,586,398 provides an article of footwear for more efficient running and walking wherein the contour of the outer sole at the heel is formed at a dihedral angle to the medial/forefoot portions in order to delay the instant of initial contact and thereby allow a longer length of foot flight and correspondingly longer stride length. An additional embodiment provides for friction management through materials selection, surface coatings, or surface treatments designed to affect friction across one or more interfaces between foot plantar surface and shoe insole.
U.S. Pat. No. 5,647,145 describes a sculptured sole for an athletic shoe comprising a plurality of forward support pads, rearward support lands, a layer of flexible resilient elastic material interconnecting various components, as well as a plurality of channels, grooves, slots and the like, which complement the natural flexing actions of the muscles of the heel, metatarsals and toes of the foot.
U.S. Pat. No. 5,680,714 discloses a trampoline effect athletic shoe having elastic return strips running across the sole of the shoe and supported above the bottom surface in a gap between the outsole and insole.
U.S. Pat. No. 5,829,172 relates to shoe soles of running shoes, particularly for 100 m sprints and the like. The object of the invention is to prevent the heel from touching the ground during running and thereby prevent a decrease in running efficiency. The sole comprises a thickly formed forefoot section for receiving spikes. A Reinforcing member provided in the ball region of the foot is integrated with reward-projecting medial and lateral ribs to form a wedge-shaped plane extending toward the heel. Medial and lateral ribs and reinforcing member form a wedge-shaped inclined plane extending form the ball to the arch of the foot, which serves to maintain the weight distribution of the runner over the ball of the foot and hold the heel of the foot in an elevated position.
U.S. Pat. No. 5,743,028 describes a spring-air shock absorption and energy return device for shoes in which a shoe heel insert is provided having a heel-shaped outer spring mechanism which serves as an internal spring housing wherein a plurality of compression springs are retained, and wherein the entire unit is filled with a pressurized gas and hermetically sealed.
U.S. Pat. No. 5,87,568 pertains to an athletic shoe wherein the sole has a rounded heel strike area and gently curved bottom that gradually thins towards the toe section to permit the runner to roll smoothly forward from the initial heel strike. Additional embodiments further provide for a shock-absorbing insert in the heel section.
U.S. Pat. No. 5,937,544 provides athletic footwear wherein the sole includes a foundation layer of semi-flexible material attached to the upper and defining a plurality of stretch chambers, a stretch layer and a thruster layer attached to the stretch layer such that interactions can occur between the foundation layer, stretch layer and thruster layer in response to compressive forces applied thereto so as to convert and temporarily store energy applied to regions of the sole by wearer's foot into mechanical stretching of the portions of the stretch layer into stretch chambers. The stored applied energy is thereafter retrieved in the form of rebound of the stretched portions of the stretch layer and portions of the thruster layer.
U.S. Pat. No. 6,006,449 and U.S. Pat. No. 6,009,636 relates to footwear having various forms of spring assemblies incorporated into the sole, which serve to absorb shock and transfer energy.
The foregoing and other known prior art have fundamental disadvantages in that they are not directed at improving efficiency by synchronizing the three basic phases of the human running cycle, seen illustrated in FIGS. 6A-6C with elements on the shoe that optimize momentum, efficiency, and fluidity of motion through the cycle. For example, prior art shoes place the wearer in a plantigrade stance, as shown in FIG. 7. Generally, a plantigrade stance is created between the balance of two points: one at the calcaneous and the other at the metatarsal/phalanges joints. Relative to the digitigrade stance provided through the novel embodiments of the present invention described below, plantigrade shoe systems are inefficient in that in subject the wearer of the shoe systems to greater breaking forces during running cycles.
Rather than hydraulic or pneumatic systems; mechanical spring and/or lever assemblies; resilient elastic bands; alteration of the heel-strike region; or reinforcing structures to maintain the heel in an elevated position, the present invention provides systems and methods that promote efficient running technique by providing a sole comprising a specially designed foot-strike member and balance-thrust member, which are integrated with a unique pivot and balance structure that displaces the wearer's center of gravity when running, thereby transferring gravitational, inertial and ground reaction forces, as well as muscular tension generation into linear momentum. Systems and methods of the present invention are an advance in the field of athletic shoe technology by providing a specialized sole design for redirecting the forces encountered during running into linear momentum, while reducing the shock and trauma to the body. The present invention provides novel footwear and components thereof for achieving a more efficient centering of mass that helps improve transfer of momentum energy to a stable platform for propulsion during toe-off (propulsion) phase of gait.